JSON::XS is a Perl module for converting arbitrary Perl data structures to
JSON and vice versa. Its primary objectives are to be semantically correct
and to run quickly; for the latter goal, the implementation is written in C.

From JSON version 2.0 onward, the JSON module will use JSON::XS to accelerate
its work, with no overhead due to emulation (by inheriting the constructor
and methods). Using JSON instead of JSON::XS gives you a portable JSON API
that can be fast when needed, but doesn't require a C compiler by falling
back on a Pure Perl implementation.